Single channel activity associated with the calcium dependent outward current inHelix pomatia

1981 ◽  
Vol 389 (3) ◽  
pp. 293-295 ◽  
Author(s):  
H. D. Lux ◽  
E. Neher ◽  
A. Marty
Keyword(s):  
Single Channel ◽  
Outward Current ◽  
Channel Activity ◽  
Calcium Dependent ◽  
Single Channel Activity

scholarly journals Myotubes from transgenic mdx mice expressing full-length dystrophin show normal calcium regulation.

1994 ◽  
Vol 5 (10) ◽  
pp. 1159-1167 ◽  
Author(s):  
W F Denetclaw ◽  
F W Hopf ◽  
G A Cox ◽  
J S Chamberlain ◽  
R A Steinhardt
Keyword(s):  
Single Channel ◽  
Calcium Regulation ◽  
Full Length ◽  
Mdx Mice ◽  
Free Calcium ◽  
Muscle Degeneration ◽  
Channel Activity ◽  
Mouse Muscle ◽  
Calcium Dependent ◽  
Normal Calcium

A lack of dystrophin results in muscle degeneration in Duchenne muscular dystrophy. Dystrophin-deficient human and mouse muscle cells have higher resting levels of intracellular free calcium ([Ca2+]i) and show a related increase in single-channel open probabilities of calcium leak channels. Elevated [Ca2+]i results in high levels of calcium-dependent proteolysis, which in turn increases calcium leak channel activity. This process could initiate muscle degeneration by further increasing [Ca2+]i and proteolysis in a positive feedback loop. Here, we tested the direct effect of restoration of dystrophin on [Ca2+]i and channel activity in primary myotubes from mdx mice made transgenic for full-length dystrophin. Transgenic mdx mice have been previously shown to have normal dystrophin localization and no muscle degeneration. Fura-2 calcium measurements and single-channel patch recordings showed that resting [Ca2+]i levels and open probabilities of calcium leak channels of transgenic mdx myotubes were similar to normal levels and significantly lower than mdx littermate controls (mdx) that lack dystrophin. Thus, restoration of normal calcium regulation in transgenic mdx mice may underlie the resulting absence of degeneration.

scholarly journals Spontaneous single-channel activity of mouse TRP5 channel recombinantly expressed in HEK293 cells

2000 ◽  
Vol 82 ◽  
pp. 131
Author(s):  
Minoru Wakamori ◽  
Hisanobu Yamada ◽  
Takaharu Okada ◽  
Keiji Imoto ◽  
Yasuo Mori
Keyword(s):  
Single Channel ◽  
Hek293 Cells ◽  
Channel Activity ◽  
Single Channel Activity

Lactate inhibits Ca2+-activated Ca2+-channel activity from skeletal muscle sarcoplasmic reticulum

1997 ◽  
Vol 82 (2) ◽  
pp. 447-452 ◽  
Author(s):  
Terence G. Favero ◽  
, Anthony C. Zable ◽  
, David Colter ◽  
Jonathan J. Abramson
Keyword(s):  
Skeletal Muscle ◽  
Sarcoplasmic Reticulum ◽  
Single Channel ◽  
Channel Activity ◽  
Release Channel ◽  
Muscle Lactate ◽  
Tension Development ◽  
Contraction Coupling ◽  
Single Channel Activity ◽  
High Concentrations

Favero, Terence G., Anthony C. Zable, David Colter, and Jonathan J. Abramson. Lactate inhibits Ca2+-activated Ca2+-channel activity from skeletal muscle sarcoplasmic reticulum. J. Appl. Physiol. 82(2): 447–452, 1997.—Sarcoplasmic reticulum (SR) Ca2+-release channel function is modified by ligands that are generated during about of exercise. We have examined the effects of lactate on Ca2+- and caffeine-stimulated Ca2+ release, [3H]ryanodine binding, and single Ca2+-release channel activity of SR isolated from rabbit white skeletal muscle. Lactate, at concentrations from 10 to 30 mM, inhibited Ca2+- and caffeine-stimulated [3H]ryanodine binding to and inhibited Ca2+- and caffeine-stimulated Ca2+ release from SR vesicles. Lactate also inhibited caffeine activation of single-channel activity in bilayer reconstitution experiments. These findings suggest that intense muscle activity, which generates high concentrations of lactate, will disrupt excitation-contraction coupling. This may lead to decreases in Ca2+ transients promoting a decline in tension development and contribute to muscle fatigue.

Delayed-rectifier potassium channel activity in isolated membrane patches of guinea pig ventricular myocytes

1991 ◽  
Vol 260 (4) ◽  
pp. H1390-H1393 ◽  
Author(s):  
K. B. Walsh ◽  
J. P. Arena ◽  
W. M. Kwok ◽  
L. Freeman ◽  
R. S. Kass
Keyword(s):  
Guinea Pig ◽  
Single Channel ◽  
Ventricular Myocytes ◽  
Outward Current ◽  
Time Dependent ◽  
Delayed Rectifier ◽  
Potential Range ◽  
Ammonium Compound ◽  
Channel Activity ◽  
Patch Clamp Technique

When the patch-clamp technique was used, a slowly activating, time-dependent outward current was identified in both cell-attached and excised membrane patches obtained from guinea pig ventricular myocytes. This macroscopic patch current was present in approximately 50% of patches studied and could be observed both in the presence and absence of unitary single channel activity (i.e., ATP-sensitive K+ channels). The time course of activation of the patch current resembled that of the whole cell delayed-rectifier K+ current (IK) recorded under similar ionic conditions, and the patch current and IK were activated over a similar membrane potential range. The time-dependent patch current could be eliminated when the Nernst potential for K+ equaled that of the pulse voltage. The patch current was inhibited by external addition of the tertiary ammonium compound LY 97241 (50 microM) and was augmented after internal application of the catalytic subunit of adenosine 3',5'-cyclic monophosphate-dependent protein kinase (500 nM). Deactivating tail currents with kinetics similar to those of IK could be recorded to cell-attached and excised patches. Unitary single channel events underlying the time-dependent patch current could not be resolved despite various attempts to increase single channel conductance. Thus our results suggest that a major component of delayed rectification in guinea pig ventricular cells is due to the activity of a high-density, extremely low conductance K+ channel.

A metal-supported biomimetic micromembrane allowing the recording of single-channel activity and of impedance spectra of membrane proteins

2010 ◽  
Vol 78 (2) ◽  
pp. 176-180 ◽  
Author(s):  
Lucia Becucci ◽  
Massimo D'Amico ◽  
Salvatore Daniele ◽  
Massimo Olivotto ◽  
Andrea Pozzi ◽  
...  
Keyword(s):  
Membrane Proteins ◽  
Single Channel ◽  
Impedance Spectra ◽  
Channel Activity ◽  
Single Channel Activity

scholarly journals Probing Amphotericin B Single Channel Activity by Membrane Dipole Modifiers

PLoS ONE ◽  
2012 ◽  
Vol 7 (1) ◽  
pp. e30261 ◽  
Author(s):  
Olga S. Ostroumova ◽  
Svetlana S. Efimova ◽  
Ludmila V. Schagina
Keyword(s):  
Amphotericin B ◽  
Single Channel ◽  
Channel Activity ◽  
Single Channel Activity
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